from typing import Any

from core.Expando import Expando
from workflow.engine import DataPresenter


class DefaultDataPresenter(DataPresenter):
  """Default data presenter that returns the input data unchanged."""
  
  def __init__(self, component_id: str, mappings_definition: str):
    super().__init__(component_id)
    self._mappings_definition = mappings_definition
    self._split_definitions = [definition.strip() for definition in mappings_definition.split(",")]
    
    if "*" not in mappings_definition:
      self._static_mappings = self._get_static_mappings()
    else:
      self._static_mappings = None
  
  def present(self, data: Any) -> Any:
    self._validate_mappings_definition()
    
    if self._static_mappings:
      return Expando(data.to_dict(self._static_mappings))
    
    dynamic_mappings = self._get_dynamic_mappings(data)
    return Expando(data.to_dict(dynamic_mappings))
  
  def _get_dynamic_mappings(self, data):
    
    manage_conflicts = {}
    
    mappings = {}
    for mapping in self._split_definitions:
      if "=" in mapping:
        key, value = [s.strip() for s in mapping.split('=', 1)]
        if key == "*":
          # all fields
          if value != "*":
            raise ValueError("Only '*' is accepted when renaming wildcard.")
          for key in data.as_dict().keys():
            if key in manage_conflicts:
              raise ValueError(f"Collision detected for field '{key}'. It is mapped from both '{manage_conflicts[key]}' and '{mapping}'.")
            manage_conflicts[key] = mapping
            mappings[key] = key
        elif key.endswith(".*"):
          # all fields in a sub-object
          if value != "*" and value != "":
            raise ValueError("Only '*' is accepted when renaming wildcard.")
          obj_path = key[:-2]
          sub_obj = data.get(obj_path)
          if isinstance(sub_obj, dict):
            for sub_field in sub_obj:
              if sub_field in manage_conflicts:
                raise ValueError(
                  f"Collision detected for field '{sub_field}'. It is mapped from both '{manage_conflicts[sub_field]}' and '{mapping}'.")
              manage_conflicts[sub_field] = mapping
              mappings[f"{obj_path}.{sub_field}"] = sub_field
          else:
            raise ValueError(f"Field '{obj_path}' is not an object.")
        else:
          mappings[key.strip()] = value.strip()
      
      
      else:
        if mapping == "*":
          # all fields
          for key in data.as_dict().keys():
            mappings[key] = key
        elif mapping.endswith(".*"):
          # all fields in a sub-object
          obj_path = mapping[:-2]
          sub_obj = data.get(obj_path)
          if isinstance(sub_obj, dict):
            for sub_field in sub_obj:
              mappings[f"{obj_path}.{sub_field}"] = f"{obj_path}.{sub_field}"
          else:
            raise ValueError(f"Field '{obj_path}' is not an object.")
        else:
          mappings[mapping] = mapping
    
    return mappings
  
  def _get_static_mappings(self):
    mappings = {}
    for mapping in self._split_definitions:
      if "=" in mapping:
        key, value = [s.strip() for s in mapping.split('=', 1)]
        if not value:
          value = key.split(".")[-1]
        mappings[key] = value
      else:
        mappings[mapping] = mapping
    
    return mappings
  
  def _validate_mappings_definition(self):
    last_char_was_comma = False
    for i, char in enumerate(self._mappings_definition):
      if char == ',':
        if last_char_was_comma:
          raise ValueError(f"Invalid mappings definition: Error found at index {i}")
        last_char_was_comma = True
      elif not char.isspace():
        last_char_was_comma = False